The use of radio-frequency identification (RFID) devices in the retail industry has started to become widespread as retailers have realized the potential of these small and inexpensive devices. A RFID tag, which can be placed onto a product offered for sale, can permit the retailer to automatically track movement of the product, perform automatic check-out of the customer (including instant debiting of the customer's account), automatic inventory control, locating misplaced product, and so forth. The use of the RFID devices can also provide the retailers with information regarding the customers, such as their purchasing habits, their movement patterns through the retail store, and so on.
RFID devices that are implanted onto products (commonly referred to as RFID tags) are usually powerless radios (in some applications, the RFID tags can have an external power source, typically, a battery) with a small amount of memory and perhaps a controller or a processor. The RFID tags receive power only when they are energized by RF signals from a RFID reader. A rectifier coupled to an antenna in the RFID tag can convert energy in the RF signals into electrical energy to power the RFID tag. Once powered, the RFID tag can respond to probes from the RFID reader and provide information stored in its memory or execute instructions provided by the RFID reader.
A possible use of RFID tags is to track product sales and potentially associate a product with the person who purchased it. Since each RFID tag can be assigned a unique identification number, not only can the purchaser be associated with a particular product, the purchaser can be uniquely associated with a unique instance of the particular product. For example, the purchaser of a blue shirt can be associated with blue shirt number 17. This unique association can be used by the retailer to curtail problems such as the purchaser purchasing a product and then later buying the same product and returning the previously purchased product. This practice can result in the retailer being forced to accept a return of a used product that cannot be resold and taking a financial loss as a result.
Unfortunately, the RFID tags can also be exploited to infringe the privacy of a customer. For example, if the purchaser of the blue shirt returns to the retailer where the blue shirt was purchased, then RFID readers can retrieve the purchase history of the purchaser using the RFID tag embedded in the blue shirt to direct targeted advertising at the purchaser.
A technique that can be used to help protect the privacy of the customer is to damage (or destroy) the RFID tag after the customer makes a purchase. The damaged RFID tag can no longer provide information since it is inoperable.
Another technique that can be used is to require that a specific sequence of commands be provided to the RFID tag before it would provide unique identifying information to an RFID reader.
One disadvantage of the prior art is that physically destroying the RFID tag at the point of purchase will prevent the retailer from reusing the RFID tag should the customer return the items in an unused, re-sellable state. The retailer would then have to replace the damaged RFID tag with a working one or choose to not be able to take advantage of the functionality of the RFID tag for the returned items.
A second disadvantage of the prior art is that it can be possible to provide the RFID tag with the specific sequence of commands while the customer is in the store and retrieve the unique identifying information. Since the retailer knows the specific sequence of commands needed to retrieve the unique information from the RFID tag, this technique offers very little to no privacy protection for the customer.